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Period: 500 to 500
Democritus
460-370 B.C.. Suggested that matter could not be infinitely divided. Coined the term atom.daild to find out what held atoms together. -
Period: Aug 24, 600 to Aug 25, 600
Aristotle
384-322 B.C.. Disagreed with Democritus.completely denied the idea of the atom because of his personal beliefs -
Period: to
John Dalton
English schoolteacher that who marks the beginning of modern atomic theory. Belived atoms are the smaller particle. -
Period: to
J.J Thompson
Designed a series of CRT experiments at Cambridge. To determine the ratio of the partle charged to its mass. Concluded the mass of the particle was much smaller than that of the hydrogen atom. Disproved Dalton's theory. Won the noble prize in 1906. -
Period: to
Robert Millikan
Designed oil drop appersrus to determine the charge of the electron. Concluded it had a negative charge of -1. -
Period: to
Ernest Rutherford
Studies how positively changed a-particle interacted with solid matter. He calculated that the atom was mostly just empty space. -
Period: to
James Chadwick
Demonstrated that the necleus had a neutral sub atomic particle, the neutron. Won noble prize in 1935.